Posted
by
Soulskill
on Friday February 14, 2014 @03:10PM
from the hot-topic dept.

cartechboy writes "The safety headlines involving the Tesla Model S were a mixed bag last year. The good news was the Model S received a top safety rating, but the bad news came with three of those electric cars catching fire after receiving damage to the battery packs. (Though coverage of the latter was disproportionate to the coverage of fires in other types of vehicle.) Now another Tesla Model S has caught fire, but this time the car was parked and unplugged. The fire happened earlier this morning in the owner's garage in Toronto, Ontario. At this time no one knows what sparked the fire, but we do know the vehicle was only about four months old. Again, it wasn't plugged into a charging station, and it wasn't turned on. With no one near it. Interestingly, the battery on this particular Model S was unscathed by the fire. In fact, the Toronto fire department says the fire didn't originate in the battery, the charging system, the adapter or electrical receptacle since all of those components weren't touched by the fire. So, how did this Tesla fire happen, and will this blow up into a larger issue for the new automaker?"

"In fact, the Toronto fire department says the fire didn't originate in the battery, the charging system, the adapter or electrical receptacle since all of those components weren't touched by the fire"

maybe the fire was cause by something in the garage adjacent to the car?

Clearly GM set the fire intentionally and then paid off the fire department to say it was the Tesla, but the fire department failed to make it convincing! WAKE UP SHEEPLE! There's a vast incompetent conspiracy going on!

Absolutely, I'm surprised it wasnt more. Tesla is still a relatively small car company, and every employee there has alot of "skin in the game" so to speak. Most likely, the Tesla group consisted of: Two engineers, Probably a battery specialist, and someone familier with the high power electronics. You're going to get the individual who is responsible for the entire engineering team who designed the model. Probably a VP and a product manager as well. Thats five without batting an eye. Thats just the techni

A friend of mine had a house fire whose origin could not be reliably determined. It's not all that uncommon for the source of a fire to be unresolved. That's almost worse for Tesla as it plants the seed of doubt in a way that can't be readily defended against. Even a citing of some feature of the car could be better as that feature or aspect could be changed, but if the cause isn't determined then there's nothing to do to fix it.

"In fact, the Toronto fire department says the fire didn't originate in the battery, the charging system, the adapter or electrical receptacle since all of those components weren't touched by the fire"

maybe the fire was cause by something in the garage adjacent to the car?

Looking at the pictures, you see that from all appearances, the car itself wasn't even involved. It simply happened to be there.

The fire department has torn down large amounts of sheet rock, trying to get at the fire, which says they thought it it was in the walls, orthe ceiling. This sounds like an electrical fire, or something hot enough to possibly have ignited the studs behind the sheet rock, so theyhave to tear it down to make sure.The firemen are paying no attention to the car, they are looking as s

I would think conservatives (like me) are a fan because Musk is an incredibly successful businessman, free market yadda yadda. He sells a good product, he makes successful companies, he shows how the private market is supposed to work.

I would think liberals would love tesla because its the environmentalist dream-- its a desirable product that is environmentally friendly AND viable in the real world.

Trouble with your argument is that the posters who criticise Tesla on here are mostly from the right. Just as Jeremy Clarkson, the TV presenter of Top Gear, who criticises Tesla to the point of lying, is a right wing twat.

If the fire "didn't originate in the battery, the charging system, the adapter or electrical receptacle," then the fact that the car was a Tesla is pretty much irrelevant, since those are the things that make a Tesla distinct from any other kind of car. So, this seems to have been a fire in which the car parked in the garage happened to be a Tesla, rather than something specifically Tesla related.

If the fire "didn't originate in the battery, the charging system, the adapter or electrical receptacle," then the fact that the car was a Tesla is pretty much irrelevant, since those are the things that make a Tesla distinct from any other kind of car.

Well, that is not the only thing that makes Tesla different. There are a lot more electrical components only present in electric vehicles but which are not related to the charging, battery and electrical receptacle. There is the propulsion system, electrical convertors, motors at (I assume) all four wheels, then there is all kinds of geeky, energy wasting electronic gadgetry to display to the user how much energy they are saving.

There's one motor, a direct drive linkage (no transmission), and differentials. Hub motors require all kinds of computer control, with associated high chances of fault that could much more easily lead to loss of control or efficiency. Hub motor efficiency is kind of like video poker: perfect play for 3 years straight will net you a profit, absolutely, no question you will beat the casino; the profit is small, and a single small mistake will set you back about 85 years. It only makes sense in a motorcycle, where you have one rear wheel hub motor.

Hub motors require all kinds of computer control, with associated high chances of fault that could much more easily lead to loss of control or efficiency. Hub motor efficiency is kind of like video poker: perfect play for 3 years straight will net you a profit, absolutely, no question you will beat the casino; the profit is small, and a single small mistake will set you back about 85 years. It only makes sense in a motorcycle, where you have one rear wheel hub motor.

I'm curious what leads you to those statements. What kind of extra computer control do hub wheels require beyond the obvious need for 4x the raw power transistors? What kind of problems would lead to reduced efficiency vs a single drive motor? Do hub motors have a different efficiency profile? something specific to the geometry of a hub wheel?

I would have thought that having 4 hub wheels would provide an opportunity for more efficient traction control, and better regenerative braking efficiency than a singl

I suspect it's mostly synchronization issues. Trying to get two independent motors turning at exactly the same speed is likely a major challenge, and if the speeds are even slightly different then the car will pull toward the slower one. A differential meanwhile is a relatively simple and well-understood piece of technology that does the same job (uniform wheel power with slippage compensation) more simply.

Plus the cooling system is no doubt much simpler with only a single motor that's not surrounded by a big spinning wheel.

First AC got it almost perfect - as long as you have a powered axle the wheels on both sides spin at the same speed and there is no tendency to "pull" unless they're improperly aligned or your wheels are different diameters. As multiple powered axles still all push straight forward. The only part AC got wrong was that barring slippage and assuming your wheels are all the same size, every single axle must will turn the same speed.

It's like a team of horses pulling a load - so long as all the horses are in one line you can mix hard workers and slackers however you like. Some will pull harder than others, but they all move together at the same speed. If you have two rows though, then you need to be careful to balance your horses - put all your slackers on one side and you'll start going in circles.

Then how do all of the millions of CD and DVD players out there manage to properly play the discs, or VCRs play tapes without the TV losing sync?

Matching motor speeds is easy, even without encoder feedback. If a motor is turned at a different speed than it is driven it distorts the waveform going to the motor. Modern drive electronics can sense that, and adjust accordingly.

I've worked on machines that produce fabrics at 10 - 15 feet per second, and they contain multiple motors that are perfectly synchroniz

In a mechanical system, you can have things like viscous couplers or torsion differentials. The wheels will spin at the same speed, but if one encounters less resistance then more power will move to the others. A single power unit supplies power input, which is then distributed based on the laws of physics as applied to a complex mechanical system. Gears and metal poles are lossy due to heat from flexing, compressing metal; viscous couplings are obviously more lossy because they're non-solid and thus the working fluid is experiencing far more deformation than metal.

In a hub layout, all those inefficiencies go away. Computers perfectly apply the correct amount of torque at the correct rotational speed directly to each wheel. For a given RPM, the motor will simply spin at no torque unless there is resistance, at which point it will draw more power to retain spin speed.

Unless... your calculations are slightly wrong. And the motors have loss by heat--which they do. And the computer has to calculate when to back off power to one free-spinning motor which is now heating up and spinning the wheel too god damn fast, but only after taking a sample.

Hub motor efficiency gains aren't ungodly massive; they're small, and they require perfect operation. They also require additional (powered) sensors and computer number crunching, rather than passive mechanical systems which simply cannot function in any manner besides "distribute power correctly" or "fail completely because the system is broken". Drifting sensors, poor sampling, and just the need to get enough of a sample to make a statistically significant analysis and adjust power output per wheel all rob hub motor systems of their theoretical maximum efficiency. The first of these is of particular practical importance: it's extremely easy for this system to be out of spec and inefficient without the end user knowing or caring. The rest are engineering challenges.

All of these potential failures are multiplied by the number of hub-powered wheels. An entire drive train system--a hub motor, its connection to the wheel, sensors, power connectors, regenerative braking mechanisms, and so on--must be duplicated four times to get all-wheel drive. With a single power unit in a mechanical system, you only need to build one drive train, which is simpler and only needs to be incrementally improved in very direct and simple ways. No improving computer code for the average case while trading off the better case; no attempting to get sensors to get more precise data, then trying to factor that improvement into the rest of the control system. You use better alloys, better machined gears, you use what you learn from further research to tweak the design so that it couples and transfers power more effectively and reacts more quickly and immediately to slippage.

The big driver for hub motor vehicles is all the things you can do in theory. Modern traction control and ESC applies braking force to individual wheels, whereas you could just back off the hub motor... or apply braking force by the regenerative brake. But that begs the question: aren't you using the same computer control programs for regenerative brake applied traction control as you are for hub motor regenerative brake traction control? And then of course those benefits essentially come down to the corner case of driving in terrible conditions, which is inefficient as hell anyway--and your efficiency gains are minimal.

Lots of funny theory, lots of "with X we can Y", as it has always been. One of the big pushes with Firewire was that we were going to have revolutionized home entertainment: you would have abstract equipment with IEEE1394 ports, plug a speaker into the VCR, plug another into the TV, subwoofer into a receiver deck at the back of the room daisy chained to the DVD player, and daisy chain rear room speakers off that, and all these devices would find each other through these arbitrary connections and unify themselves as your home theater. That was being heavily advertised in home theater shops for a while, but it never happened. All these things you should be able to do with your iPad never materialized. The XO Laptop hasn't met its potential yet--it has revolutionized nothing. Same with hub motors.

The rush to draw conclusions seems to be from those who are pointing the finger at the Tesla. They are the ones not waiting for the investigation. The GP was only responding to those original assumptions.

It happened in a PRIVATE garage, shortly after the owner had come back from a drive. It points pretty strongly to SOMETHING to do with the car, but they were unable to pinpoint the cause, other than it was not the charging system, battery and electric receptacle. It could have been a short in the radio for all we know, but that is still an issue with the car.

We shouldn't assume it was or wasn't from the car without even knowing the source point. But if one were to guess, the most likely answer would be an electrical short somewhere in the circuitry. Even when "off", there are still hot circuits through the vehicle. Could be something as simple as a faulty contact or connector near a source of flammable lubricant or other material. Then again, it could have been something left in the car by a passenger. Less likely, IMO, but we just won't know till we are told.

Say what? Why would they do such a thing? Perhaps the charging system needs to be always-on so that it can seamlessly detect being plugged in and regulate the charging process (not uncommon in electronics - many battery chemistry are... violently enthusiastic about unsupervised charging), but what else needs to be powered that isn't always-on in any modern car? (power locks, security system, possibly cooling control system, etc)

A short circuit in the radio for instance can cause a fire that's independent of the battery or charger.

No evidence the car was actually involved at all. The car roof isn't even burned. They haven't even bothered to open the car door.They yanked down a ton of sheet rock looking for fire. The firemen are looking at the wall and floor.

If anything, its probably the home handyman wiring installed (unprofessionally) to handle the Tesla charging.

Actually it looked like the front end was probably involved somehow, they just don't show it directly. Otherwise they would have presumably removed the Tesla along with the Lexus that was parked next to it when the fire broke out.

They yanked down a ton of sheet rock looking for fire. The firemen are looking at the wall and floor.

That's because when a structure becomes involved in a fire, even if it didn't start there, they need to make sure the fire isn't still active in the walls of the structure. It's really embarrassing for firemen to pack up after thinking they've put a fire out, only to get called back a couple of hours later because some two-by-four in the wall wasn't fully extinguished. Also dangerous for the structure owner.

Yes, but this is a rear drive car, with batteries amidship. There is no damage to the rear or the battery areas. All the glass is intact.

There is nothing in the front of the tesla that could start that fire other than the power steering assist motor. If that got hot enough to ignitewhat ever was in the boot (front trunk) you could have a small fire, but not one this big.

Given the huge amount of bad press Tesla got from the three earlier debris fires, I can totally understand why they would bend over backwards to make this guy (and hopefully the press) happy. It doesn't necessarily mean they're trying to cover something up.

As others have pointed out, garages are full of flammable stuff. Fire could have originated anywhere.

The picture in TFA sure does make it look like it originated somewhere in the front hood area of the Tesla. If it was a regular car, I could believe that he might have parked a hot engine above an oily rag, but i don't think Teslas are supposed to get hot under the hood.

That it'll be attributed to a improper maintenance/improper sealing of some kind against corrosion. It's that's the second on the list with cars up here when gasoline leaks aren't the cause. The first is of course gasoline leak related, the third is usually modifications to the exhaust system which cause body frame fires. We use *a lot* of salt on the roads here in the winter, and I mean a lot. It's just so damn cheap since we have mines for it all over the place between Ottawa and Windsor(Windsor Salt for example), and man places are in a locked in 100 year contract.

Those are probably more common (and I said one of the most common), but modern building codes require fire-resistant construction (like thicker drywall and heavy doors) between the garage and the main house for a good reason.

There are about 13,900 vehicle fires per year without structural involvement and 366,000 home structure fires of which only 8,9000 started in a garage or vehicle storage area, according to the NFPA. [nfpa.org] Cars don't even make the 1% cut-off for inclusion in their table of sources of ignition. Your washer and drier are a far bigger risk (15,200 house fires).

By far the most common causes of house fires are cooking accidents (43%), heating equipment (16%), arson (8%), faulty wiring or other electrical (6%), and sm

Alright... let's skip the distraction of tying car fires to house fires. Your report states that there were almost 14,000 car fires on residential properties that didn't start the house on fire. Presumably, many additional car fires started in cars parked in places other than peoples' homes. That adds up to tens of thousands of annual car fires that we should be worrying about in addition to this single Tesla. There ought to be dozens of car fire articles per day here on/. so that we can hash out each one.

Normal gas cars catch fire every day just sitting in peoples driveways or driving along. It's usually a short in the 12V (regular car battery) system related to one of the electronic accessories. It can happen because water gets in and corrodes a contact (like the electric windows) or heat from a nearby item like a headlamp wears down the insulation or other wear and tear that cars are subjected too. In some cases it is identified as an engineering fault rather then a unique occurance in which case a recall occurs. If you go back 3 years you can probably find at least one recall for each of the major manufacturers to fix an electrical fault that 'could lead to a fire'.

Having some basic knowledge [slashdot.org] about car fires makes it clear just how much Tesla fires are about media hype.

Are you basing this percentage on the number of sensational reports in the media, or from actual stats?

This "story" already screams click bait. "Tesla catches fire and zomg it wasn't plugged and and no one was near it! - Ignore the fact that the fire department has said that there is no fire damage anywhere on the electrical components or battery, just keep clicking on 'tesla' 'fire' 'zomg!' links guys".

If this turns out to be something related to the Model S then *maybe* it is news, but right now it looks

Well, if I look at the number of cars in the US (254 million or so) vs. number of car fires per year (152 thousand or so on average), and then look at the number of Telsas sold vs. number of Teslas involved in car fires, the rate for Teslas is a third to a quarter that of gasoline-powered cars. So yes, if a gasoline-powered model had the same fire rates as Teslas and there was detailed coverage of every single fire it was involved in I'd make an accusation of media hype, how else would you explain that focus accompanied by a lack of coverage of models that catch fire 3-4x as often?

No, in point of fact, the car would be assumed to be a commercial success if the gas car caught on fire as few times as the Tesla has. Those stats have already been shown over and over. You can now go collect your paycheck at BMW.

With the fire not originating in anything connected to its electrical system, why are they assuming that the fire originated in/from the car at all? It sounds highly unlikely, and more like vacuous sensationalism.

With the fire not originating in anything connected to its electrical system, why are they assuming that the fire originated in/from the car at all? It sounds highly unlikely, and more like vacuous sensationalism.

Look at the picture in TFA. It is pretty clear that the front trunk area was the most damaged area.

The front trunk area is mostly storage. Under that there is an AC unit, electric power steering, and an air fan (for cooling the batteries I guess). Presumably at most, the air fan was in operation as the car had recently returned and was parked.

Ok, it started in the tesla. It is not the battery, not the drive train, not the charger, not the computer, etc, BUT, it started in the tesla. Okkkkaaayyyy.
This sounds like the guy that committed suicide by shooting himself directly in the back of his head 3x with a 45.

FOD... (Foreign Object Debris) - shorting power to ground anywhere. Doesn't take much especially on a circuit board somewhere, rapidly heats up and melts solder creating and even bigger short and more heat until fire.

Dendrite formation - Very rare and probably requires more than 4 months to happen, but certain components on a high density BGA array the solder can form tendrils towards other solder balls. As the dendrites get close to each other they will short and break kind of like a fuse, but eventually it can become big enough to hold and sustain current generating enough heat to start the solder balls melting driving more current and heat until fire.

A entire car line was recalled for catching fire for no reason earlier last year. People got in hi-speed wrecks and caused fires, happening to be in a Tesla. The latter gets coverage, the former gets hardly any. No spin from what I can see here, just a disproportionate coverage on a car that's already in the spotlight.

My Ford truck burst into flames after sitting for 3 days in my driveway a couple years ago. Fortunately my wife was working from home and called the fire dept. Saved my house.

I talked to several lawyers after this and what they told me was scary:

1) ALL car models can burst into flames while not running.2) Many lawyers have their entire practice base on car fires like this.3) If no one died or was seriously injured, they won't even take the case. There are too many lucrative death cases from this sort of thing for them to bother.4) EVERY one of these lawyers said they would NEVER park any car inside a garage attached to their house. One even said he fought his fancy HOA for the right to park in his driveway instead of his garage. He won, because he had the evidence.

Someone did the math the last time this came up on slashdot and the fires per vehicle produced were about 1/3rd of average for Tesla vs the general pool of vehicles, but the counterargument was that Teslas were much newer than the average vehicle and so it wasn't necessarily a good comparison. I doubt anyone outside of an insurance company's actuary department has enough data on similar vehicle rates to know for sure. All I know is that a Tesla went through a brick wall at a high rate of speed and the drive

Yes, the headline should have read "Telsa damaged in garage fire", but that's not sensational enough. Both linked articles state the car "caused" the fire (one more indirectly regarding what "ignited"), but neither indicate that any official or anyone but a reporter's guess confirms it. For all we know, the meth lab in the basement caught fire and burned a garage with a Tesla in it.

Oh, it gets better. He turned down financial assistence from Tesla including covering the car, and the costs of the garage burning.
Also, it supposedly started with the Tesla, BUT, it was not the drive train, the motor, the batteries, the super charger, the computer, or any part of the electric system.
So, where did it start?

As I said earlier, this sounds like the guy that committed suicide by shooting himself in the back of the head 3x with a 45.

http://business.financialpost.... [financialpost.com]
When Tesla offers to pay the owner of the car for the damages to his home, the guy declines. Now, call me stupid, but that's a little weird no?

Its not really that unusual. He likely has fire insurance that will cover the damage to his house and would rather deal with the insurance company than directly with Tesla. The insurance company can send the bill to Tesla and deal with the hassle, administrative details and lawyers, rather than the car owner.